Extract complex npm scripts to separate files

scripts/generate:env.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+echo > deployment/.env
+
+./.venv/bin/python3 backend/generate_vapid_keys.py >> deployment/.env
+
+cat >> deployment/.env <<EOF
+JWT_SECRET="$(openssl rand -base64 32)"
+TURN_USERNAME=<set>
+TURN_SECRET=<set>
+EOF